This proposal is to request support for a Keystone Symposia meeting entitled "Pattern Recognition Molecules and Immune Sensors of Pathogens", organized by Jenny P. Ting, Richard A. Flavell and Luke A.J. O'Neill, which will be held in Banff, Alberta, Canada from March 29 - April 3, 2009. The discovery of evolutionarily conserved immune genes and pathways has led to an explosive discovery phase in innate immunity. These pathways include TLR, NLR, C-type lectin Receptor, and the helicase-containing anti-viral proteins. These novel pathways merge the innate and adaptive branches of immunity, and converge on a wide range of disorders including infectious diseases, inflammation and autoimmunity. All of the above have systemic effects that can affect the outcome of a wide range of diseases ranging from cancer to cardiovascular disorders. Opportunities for interdisciplinary interactions will be further enhanced by the concurrent meeting "Dendritic Cells", which will share a plenary session, a workshop, and a keynote with this meeting.